This invention relates to a method of fusion splicing single-mode optical fibers using an arc discharge.
In fusion splicing single-mode optical fibers using an arc discharge, it is necessary to center cores 12.sub.1 and 12.sub.2 of optical fibers 10.sub.1 and 10.sub.2 to be spliced for low loss splicing (FIG. 1). Thereafter, optical fibers 10.sub.1 and 10.sub.2 are subjected to fusion splicing with an arc discharge. However, cores 12.sub.1 and 12.sub.2 of optical fibers 10.sub.1 and 10.sub.2 to be spliced are generally displaced from the axes 14.sub.1 and 14.sub.2 of optical fibers 10.sub.1 and 10.sub.2, respectively, as shown in FIG. 1. Therefore, when cores 12.sub.1 and 12.sub.2 of optical fibers 10.sub.1 and 10.sub.2 are centered to each other, axes 14.sub.1 and 14.sub.2 of optical fibers 10.sub.1 and 10.sub.2 have therebetween displacement or distance D, as shown in FIG. 1. When optical fibers 10.sub.1 and 10.sub.2 are spliced using an arc discharge, surface tension occurs at the spliced portion of optical fibers 10.sub.1 and 10.sub.2 to reduce displacement D. Therefore, cores 12.sub.1 and 12.sub.2 of optical fibers 10.sub.1 and 10.sub.2 are sloped at the spliced portion, as seen in FIG. 2. The slope causes a loss in fusion splicing. A large slope in spliced cores 12.sub.1 and 12.sub.2 makes it impossible to obtain a low loss splicing of spliced optical fibers 10.sub.1 and 10.sub.2. Also it is required for the spliced optical fibers to have at least a certain mechanical strength.